The honeycomb structures used in the exhaust gas purification apparatuses for the automotive internal engines include a monolith type one, an aggregate type one formed a plurality of honeycomb units joined together with a sealant, and the like.
Many of the aggregate type honeycomb structures use the sealant (adhesive) to integrally assemble the honeycomb units together. As the sealant, there is used a mixture of, for example, ceramic particles of carbide, nitride or the like, which is high in thermal conductivity for an increased regeneration efficiency, and an inorganic binder as an additive (as in the Japanese Unexamined Patent Publication No. 28246/1996). The honeycomb structure disclosed in the Japanese Unexamined Patent Publication No. 28246/1996 uses a ceramic having a high thermal conductance as the sealant to join the honeycomb units together.